A typical pregnancy lasts, on average, 280 days, or 40
weeks - starting with the first day of your last normal
menstrual period (LMP) as day 1. An estimated due date
(EDD) can be calculated by following steps 1 through 3:

1.

First, determine the first day of your last menstrual
period. If you do not know the exact date, calculate
as close as possible.

2.

Next,
count back three calendar months from that date.

3.

Lastly,
add one year and seven days to that date.

You
may also estimate your delivery date by entering
the first day of your last menstrual period
here:

Your
estimated due date is:

This estimate is
based on your last menstrual period and estimated date of conception.
If you think you may be pregnant, it is advised to consult your
physician right away.